arm64: dts: qcom: sc7180-trogdor: Make clamshell/detachable fragments

arm64: dts: qcom: sc7180-trogdor: Make clamshell/detachable fragments

At a high-level, detachable Trogdors (sometimes known as Strongbads)
don't have a cros_ec keyboard, while all clamshell Trogdors (only known
as Trogdors) always have a cros_ec keyboard. Looking closer though, all
clamshells have a USB type-A connector and a hardwired USB camera. And
all detachables replace the USB camera with a MIPI based one and swap
the USB type-a connector for the detachable keyboard pogo pins.

Split the detachable and clamshell bits into different files so we can
describe these differences in one place instead of in each board that
includes sc7180-trogdor.dtsi. For now this is just the keyboard part,
but eventually this will include the type-a port and the pogo pins.

Cc: cros-qcom-dts-watchers@chromium.org
Cc: Bjorn Andersson <andersson@kernel.org>
Cc: Konrad Dybcio <konrad.dybcio@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
Cc: Conor Dooley <conor+dt@kernel.org>
Cc: linux-arm-msm@vger.kernel.org
Cc: devicetree@vger.kernel.org
Cc: Pin-yen Lin <treapking@chromium.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20240604214233.3551692-4-swboyd@chromium.org
Signed-off-by: Bjorn Andersson <andersson@kernel.org>